The present invention is directed to semiconductor processes and devices.
Since the early days when Dr. Jack Kilby at Texas Instruments invented the integrated circuit, scientists and engineers have made numerous inventions and improvements on semiconductor devices and processes. The last five decades or so have seen a significant reduction in semiconductor sizes, which translates to ever increasing processing speed and decreasing power consumption. And so far, the development of semiconductors has generally followed Moore's Law, which roughly states that the number of transistors in a dense integrated circuit doubles approximately every two years. Now, semiconductor processes are pushing toward below 20 nm, where some companies are now working on 14 nm processes. Just to provide a reference, a silicon atom is about 0.2 nm, which means the distance between two discrete components manufactured by a 20 nm process is just about one hundred silicon atoms.
Manufacturing semiconductor devices are thus becoming more and more challenging and pushing toward the boundary of what is physically possible. Huali Microeletronic Corporation™ is one of the leading semiconductor fabrication companies that has focused on the research and development of semiconductor devices and processes.
One of the recent developments in semiconductor technologies has been utilization of silicon germanium (SiGe) in semiconductor manufacturing. For example, SiGe can be used for manufacturing of complementary metal-oxide-semiconductor (CMOS) with adjustable band gap. While conventional techniques exist for SiGe based processes, these techniques are unfortunately inadequate for the reasons provided below. Therefore, improved methods and systems are desired.
A further understanding of the nature and advantages of various embodiments may be realized by reference to the following figures. In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.